Btrfs: Throttle tuning
This avoids waiting for transactions with pages locked by breaking out
the code to wait for the current transaction to close into a function
called by btrfs_throttle.
It also lowers the limits for where we start throttling.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 4765248..b003b43 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2526,6 +2526,9 @@
*level = 0;
break;
}
+ if (printk_ratelimit())
+ printk("leaf ref miss for bytenr %llu\n",
+ (unsigned long long)bytenr);
}
next = btrfs_find_tree_block(root, bytenr, blocksize);
if (!next || !btrfs_buffer_uptodate(next, ptr_gen)) {
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 388ac39..d3f2fe0 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -253,7 +253,7 @@
end_of_last_block = start_pos + num_bytes - 1;
lock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
- trans = btrfs_start_transaction(root, 1);
+ trans = btrfs_join_transaction(root, 1);
if (!trans) {
err = -ENOMEM;
goto out_unlock;
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 52c5524..66af514 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -124,17 +124,12 @@
return 0;
}
-struct btrfs_trans_handle *start_transaction(struct btrfs_root *root,
- int num_blocks, int join)
+static void wait_current_trans(struct btrfs_root *root)
{
- struct btrfs_trans_handle *h =
- kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
struct btrfs_transaction *cur_trans;
- int ret;
- mutex_lock(&root->fs_info->trans_mutex);
cur_trans = root->fs_info->running_transaction;
- if (cur_trans && cur_trans->blocked && !join) {
+ if (cur_trans && cur_trans->blocked) {
DEFINE_WAIT(wait);
cur_trans->use_count++;
while(1) {
@@ -154,6 +149,18 @@
}
put_transaction(cur_trans);
}
+}
+
+struct btrfs_trans_handle *start_transaction(struct btrfs_root *root,
+ int num_blocks, int join)
+{
+ struct btrfs_trans_handle *h =
+ kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
+ int ret;
+
+ mutex_lock(&root->fs_info->trans_mutex);
+ if (!join)
+ wait_current_trans(root);
ret = join_transaction(root);
BUG_ON(ret);
@@ -200,7 +207,7 @@
return 0;
}
-void btrfs_throttle(struct btrfs_root *root)
+static void throttle_on_drops(struct btrfs_root *root)
{
struct btrfs_fs_info *info = root->fs_info;
@@ -223,19 +230,28 @@
} while (thr == atomic_read(&info->throttle_gen));
if (harder_count < 5 &&
- info->total_ref_cache_size > 5 * 1024 * 1024) {
+ info->total_ref_cache_size > 1 * 1024 * 1024) {
harder_count++;
goto harder;
}
if (harder_count < 10 &&
- info->total_ref_cache_size > 10 * 1024 * 1024) {
+ info->total_ref_cache_size > 5 * 1024 * 1024) {
harder_count++;
goto harder;
}
}
}
+void btrfs_throttle(struct btrfs_root *root)
+{
+ mutex_lock(&root->fs_info->trans_mutex);
+ wait_current_trans(root);
+ mutex_unlock(&root->fs_info->trans_mutex);
+
+ throttle_on_drops(root);
+}
+
static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
struct btrfs_root *root, int throttle)
{
@@ -256,7 +272,7 @@
kmem_cache_free(btrfs_trans_handle_cachep, trans);
if (throttle)
- btrfs_throttle(root);
+ throttle_on_drops(root);
return 0;
}